Raiz quadrada por fatoração
[tex]\begin{array}{r|l}\sf81&\sf3\\\sf27&\sf3\\\sf9&\sf3\\\sf3&\sf3\\\sf1\end{array}[/tex]
[tex] \mathsf{ \sqrt{81}=\sqrt{3^2\cdot3^2}} [/tex]
[tex] \mathsf{\sqrt{81}=3\cdot3 } [/tex]
[tex]\boxed{\boxed{\mathsf{\sqrt{81}=9 }}}[/tex]
